I use the backhanded flip when throwing a slow change up. In my experience, however, it's sometimes so slow that it gives the batter just enough time to reload her bat and take it deep into the outfield. Granted, it throws most batters off to the point that they're laughing at themselves because they just looked so silly swinging seconds before the pitch came; but it's those who are quick enough to regroup and reload that have forced me to rethink my whole strategy when it comes to change ups.
Most often, I use an off-speed, as opposed to a change up, to throw my batters off. I use the stiff wrist method. I hold the ball with my index finger and thumb around the backwards "C" on the threads. I come around in motion just like I would a fastball then as I release I kind of push the ball with a stiff wrist to get it across the plate just enough slower to throw the batter off completely. When I look down after releasing, my fingers that were once on the seams, are still in the shape of a "U". I hope that makes sense!
It is my best pitch by far. I'll throw it with a full count or on a 3-0 count without thinking twice. They never expect it then!